[P2-E9.3] CI integration

**Context.** The suites above join the repo's CI with pragmatic sharding and log-gate
hygiene, so flake noise does not erode trust in the signal.

**Deliverable.** CI wiring for the two-sync jobs; canton-log ignore patterns audited for
the new components (version-agnostic patterns — no pinned patch versions); flake
quarantine process documented.

**Acceptance.** Suites run per-PR; a deliberate red fails the gate; one week of runs
with no infra-red requiring manual rerun.

**Depends on.** P2-E9.1, P2-E9.2.

—
Epic: #72 · Plan: [P2-E9-testing.md](https://github.com/ChainSafe/canton-extending-mainnet/blob/main/docs/planning/phase-2-epics/P2-E9-testing.md)

Start by reading docs/planning/phase-2-epics/P2-E9-testing.md and the deliverables from P2-E9.1 and P2-E9.2. Then inspect the repository's CI configuration and the two-sync job outputs. Done means per-PR suites, deliberate failures blocking the gate, audited version-agnostic canton-log patterns, documented flake quarantine, and one week without infrastructure reds requiring reruns.

Written by the indexing model from the issue text.